Created APiKeyService and tests

module/Rest/src/Service/ApiKeyServiceInterface.php

@@ -0,0 +1,31 @@
+<?php
+namespace Shlinkio\Shlink\Rest\Service;
+
+use Shlinkio\Shlink\Rest\Entity\ApiKey;
+
+interface ApiKeyServiceInterface
+{
+    /**
+     * Creates a new ApiKey with provided expiration date
+     *
+     * @param \DateTime $expirationDate
+     * @return ApiKey
+     */
+    public function create(\DateTime $expirationDate = null);
+
+    /**
+     * Checks if provided key is a valid api key
+     *
+     * @param string $key
+     * @return bool
+     */
+    public function check($key);
+
+    /**
+     * Disables provided api key
+     *
+     * @param string $key
+     * @return ApiKey
+     */
+    public function disable($key);
+}